bios/main.c: enable flash and netboot again
top.py, lm32_config.v, linker.ld: use static hardcoded rom for bios
spiflash: add read-only variable data width spi flash
lx9crg: add crg for lx9 microboard
make.py, top.py: tweaks for lx9 microboard

sdram is 64M on lx9 microboard

lx9 only needs 320k config mem in flash
tdcdtc: preliminary version of serdes based TDC+DTC wishbone peripheral
memtest: shrink memtest space to 32M for lx9 microboard
common.mak: -Os instead of -O3, smaller bios (<32k), most embedded systems end up using -Os